Looking at your site too, are you actually just using thr Wix Login Bar from the Wix Members app and Wix own custom login and signup form as here.
https://support.wix.com/en/article/creating-a-custom-signup-form-for-your-members-area
Or did you actually make up your own custom lightboxes for login and signup and changed your member signup to corvid.
https://support.wix.com/en/article/corvid-enabling-custom-site-registration